FROM POTTS HILL (AUSTRALIA) TO PUNE (INDIA): THE JOURNEY OF A RADIO ASTRONOMER

Abstract

In this paper I recapitulate my initiation into the field of radio astronomy during 1953-1955 at CSIRO, Australia; the transfer of thirty-two parabolic dishes of six-feet (1.8-m) diameter from Potts Hill, Sydney, to India in 1958; and their erection at Kalyan, near Bombay (Mumbai), in 1963-1965. The Kalyan Radio Telescope was the first modern radio telescope built in India. This led to the establishment of a very active radio astronomy group at the Tata Institute of Fundamental Research, which subsequently built two world-class radio telescopes during the last forty years and also contributed to the development of an indigenous microwave antenna industry in India. The Ooty Radio Telescope, built during 1965-1970, has an ingenious design which takes advantage of India's location near the Earth's Equator. The long axis of this 530 m × 30 m parabolic cylinder was made parallel to the Equator, by placing it on a hill with the same slope as the geographic latitude (11°), thus allowing it to track celestial sources continuously for 9.5 hours every day. By utilizing lunar occultations, the telescope was able to measure the angular sizes of a large number of faint radio galaxies and quasars with arc-second resolution for the first time. Subsequently, during the 1990s, the group set up the Giant Metrewave Radio Telescope (GMRT) near Pune in western India, in order to investigate certain astrophysical phenomena which are best studied at decimetre and metre wavelengths. The GMRT is an array of thirty fully-steerable parabolic dishes of 45 m diameter, which operates at several frequencies below 1.43 GHz. These efforts have also contributed to the recent international proposal to construct the Square Kilometre Array (SKA).